Fuel-feeding mechanism.



W. F. SMITH.

FUEL FEBDING MEGHANISM.

APPLICATION FILED JULY 1,3, 1911.

1,025,841 Patented May 7, 1912.

l y /NI-/ENVTo/e COLUMBIA PIANDGRAPM co.. WASHING-mp1, n. c.

WALTER F. SMITH, OF BALTIMORE, MARYLAND.

FUEL-FEEDING- MECI-IANISM.

Specification of Letters Patent.

Application led July 13, 1911.

Patented May '7, 1912.

Serial No. 638,354.

To all whom, il may concern Be it known that I, WALTER F. SMITH, acitizen of the United States, residing in Baltimore city and State ofMaryland, have invented new and useful Improvements in Fuel-FeedingMechanism, of which the following is a specification.

This invention relates to certain new and useful improvements in fuelfeeding mechanism, and has reference more particularly to that class ofapparatus known as underfeed stokers.

One of the objects of the invention is to provide improved means forautomatically and smoothly feeding fuel to the re box of a steam boileror other furnace.

A further object is to provide means for maintaining a stratum of greenfuel below the coked surface as the fuel is being fed to the furnace,whereby said coked surface is constantly broken up and deposited on the'furnace grate without impeding the passage of the remaining fuel, orotherwise interfering with the feed of the lat-ter.

A further object is to provide means for graduallyand automaticallydecreasing the depth of the stratum of green fuel as the latter isoperated upon by t-he feeding mechanism, whereby green coal is preventedfrom being thrown directly on the furnace grate, thus preventing smokeemission at the stack.

A further object is to provide an underfeed Stoker with an improved andnovel form of conveyer mechanism adapted to im-` part a continuousfeeding and kneading action to the fuel as the latter is fed, wherebyformation of large masses of coke and clinkers is prevented.

A further object is to provide an underfeed stoker mechanism capable ofoperation under natural draft conditions, whereby forced hand firingconditions are obtained without the aid of manual stoking, and with lessattention than is ordinarily required in hand firing.

The invention will be hereinafter fully set l particularly pointed o-utin the forth and claims.

In the accompanying drawings z--Figure 1 is a horizontal sectional viewof a furnace illustrating my improved fuel feeding mechanism in plan.Fig. 2 is a longitudinal sectional view on the line 2 2 Fig. 1. Fig. 3is a detailed transverse sect-ional view. Fig. 4

is a detail view illust-rating one of`the conveyer members.

Referring to the drawings, 10 designates a steam boiler or other similarfurnace provided with the usual bridge wall 1l and doors 12. Each dooris provided with a hopper 13 adapted to receive fuel from any suitablesource of supply and discharge the same within the furnace in a mannerto be later described. The grate 15 may be of any suitable or preferredconstruction and eX- tends from the bridge wall to the front wall of thefurnace in the usual or preferred manner. In Fig. 1 I have shown butonehalf of the usual furnace.

Located within the furnace and communicating with the hopper 13 is aretort 20, comprising side plates 21 extending from the front wall tothe bridge wall of the furnace parallel with the grate 15, said sidesbeing united by an integral imperforate bottom 22, said sides and bottombeing preferably cast in one piece, although I do not desire to limitmyself in this particular. The bottom 22 is provided with a plurality ofstepped or inclined portions 23 forming uptakes for the fuel, saiduptakes gradually and successively increasing in height as they approachthe bridge wall of the furnace. That is to say each succeeding uptaketerminates nearer the top of the sides 21 than the next precedinguptake. Pivotally mounted adjacent the uptakes are a series of conveyermembers 24, which may be of any suitable shape. For purposes ofillustration I have shown these members in the form of a quadrant .of acircle, although I do not desire to limit myself in this particular.Each member, however, is provided with walls 25 arranged at an angle toeach other and joined by end walls 26 forming a relatively light shell.Each conveyer member is keyed or otherwise secured to a short shaft 27pivotally mounted in the sides 21 of the retort, suitable bushings 28being provided to serve as bearings for said shafts. Each conveyer is somounted with relation to one of the uptakes 23 that one of the an.-gular walls 25, in one position of the conveyer member will form apractical. continuation of said uptake, the other wall 25 serving as anabutment to force the fuel along and over the next succeeding uptake.Thus each succeeding conveyer member is mounted higher than thepreceding one. In order to prevent binding of the conveyer members byreason of fuel working 4down between the same and the uptake or otherportions of the conveyer I provide said conveyer members with lugs 29,allowing a slight clearance. The conveyer member 24 adjacent the hopper13 is arranged at a slightly different angle from the remaining conveyermembers, and the fuel entering the retort 2O through hopper 13 isdeposited directly upon said member. The conveyer members are eachprovided with crank arms, preferably formed integral with the shafts 27,and connected to links 33 extending along the sides of the retort anddriven by suitable shafting 34 which receives power in any preferredform. The operation of the links is so timed that one set of conveyermembers is moving in one direction, z'. e., to bring the wall 25 inalinement with the uptakes, and the other set of conveyers is moving inthe direction to force the fuel along the uptakes. In the arrangementshown each alternate conveyer member is connected to the link on oneside, the remaining conveyer members being connected to the link on theother side. Extending from the retort 20 to the grate 15 are aseries oftransverse grate bars 40, said grate bars spanning the space between theretort and said grate.

The operation is as follows Fuel is supplied to the hopper 13 in anypreferred manner. As the upper wall 25 of the first conveyer member 24comes into approximately horizontal position, the fuel is raisedthereby, the top surface of the fuel being usually coked by the heat ofthe furnace, just as soon as it enters the latter. The coked portion ofthe fuel, or at least a partthereof is deposited upon the grate bars 40,the stratum of green fuell below the coked surface being deposited intothe pocket formed by the other wall 25 of the conveyer member and thefirst uptake 23. The next movement of the vertical wall 25 of theconveyer member forces the fuel along the first uptake and over theVupper wall 25 of the next conveyer member. As the latter continues torise the coked surface thereabove is deposited upon the grate bars 40and the green fuel is forced along into the next uptake. Each successiveconveyer member operates in a similar manner and it will be noted thatthe operation of the conveyer members is alternate. That is, as thevertical wall of one conveyer member is moving the fuel along the nextadjacent uptake, the conveyer member at the rear end of said luptake isapproximately in alinement with the uptake. By providing the alternatelyoperating conveyer members 25, and the uptakes 23 of different heights,the fuel is fed forward smoothly and without clogging at any point. Thearrangement of the uptakes is such that a comparatively deep stratum ofgreen fuel is provided at the end of the conveyer adjacent the frontwall of the furnace, said fuel being topped by a stratum of coked fuel.The depth of the stratum of green fuel by reason of the increasingheight of the uptakes and conveyer members, gradually decreases, so thatby the time the stream of fuel reaches the bridge wall the depth of thefuel has been so diminished that practically all of it will be coked.rIhus the conveyer members will deposit thoroughly coked fuel upon gratebars 4:0 throughout the length of the retort, and practically no greenfuel reaches the grate 15. The action of the conveyer members is suchthat they not only feed the green fuel forward, but they also break upthe coked top layer of the fuel and deposit the same upon the gratebars. This is decidedly' effective in that it prevents clogging of theretort and conveyer members by the formation of solid unyielding massesof coke or clinker, which is a common experience with this class of fuelfeeding mechanism.

From the foregoing it will be seen that I have produced a fuel feedingmechanism that is very simple in construction and adapted to prevent thedeposit of green fuel upon the furnace grate, and thereby avoiding smokeemission at the stack. It will also be noted that the arrangement of themechanism is such that the furnace can operate under natural draft,thereby rendering the use of forced draft unnecessary for any and allconditions where natural draft would be sufficient for hand firing.

Having thus explained the nature of my invention and described anoperative manner of constructing and using the same, although withoutattempting to set forth all of the forms in which it may be made, or allof the forms of its use, what I claim is 1. An automatic stokercomprising a retort provided with an iinperforate bottom having spacedapartuptakes, conveyer members provided with depending walls, pivots forsaid conveyer members located in a plane above said uptakes, means forsupplying fuel to said retort, and means for operating said conveyermembers, one of the walls of each conveyer member being adapted toperiodically form a prolongation of an adjacent uptake, contiguousconveyer members being arranged to oscillate in opposite directions,whereby the fuel is alternately supported and moved in said retort.

2. An automatic stoker comprising a retort provided with an imperforatebottom having spaced apart uptakes, depending shell like conveyermembers provided with angularly disposed walls, pivots for said conveyermembers located in a plane above said uptakes, means for supplying fuelto said retort, and means for operating said conveyer members, one ofthe walls of each conveyer member being adapted to periodically form aprolongation of an adjacent uptake, contiguous conveyer members beingarranged to oscillate in opposite directions, whereby the fuel isalternately supported and moved in said retort.

3. An automatic stoker comprising a retort provided with an imperforatebottom having spaced apart uptakes, conveyer members provided withdepending angularly disposed walls, one of said walls of each con veyermember being adapted to periodically form a prolongation of an adjacentuptake, lugs formed on said conveyer members and cooperating with thebottomof the retort to 'prevent binding of the fuel, means for supplyingfuel to said retort, and means for oscillating said conveyer members.

t. An automatic stoker comprising a retort provided with an imperforatebottom having spaced apart uptakes, said uptakes being of progressivelyincreased length from front to rear, conveyer members formed withdepending angularly disposed walls, pivots for said conveyer memberslocated in a plane above said uptakes, one of said walls of eachconveyer member being adapted to periodically form a prolongation of anadjacent uptake, means for supplying fuel to said retort, and means foroscillating said conveyer members, contiguous conveyer members beingarranged to oscillate in opposite directions.

5. An automatic stoker comprising a retort having an imperforate bottom,,a hop per for directing fuel to said retort, a plurality of independentconveyer members within said retort, each formed with angularly disposeddepending walls, and means for oscillating said conveyer members, one ofsaid conveyer members being located to receive al1 the fuel entering theretort through said hopper, contiguous conveyer members being arrangedto oscillate in op* posite directions, whereby said walls alternatelysupport and move the fuel in said retort.

6. An automatic stoker comprising a retort, having an imperforatebottom, conveyer members within said retort formed with dependingangular walls, and means for oscillating said conveyer members, saidmeans including reciprocating links, the alternate conveyer membersbeing connected with one of said links, the remaining conveyer membersbeing connected with the other link, whereby contiguous conveyer membersare oscillated in opposite directions to alternately support and movethe fuel in the retort.

7. An automatic stoker comprising a retort provided with an imperforatebottom having spaced apart uptakes, conveyer mem bers formed withdepending angularly disposed walls, pivots for said conveyer memberslocated in a plane above said uptakes, one of said walls of eachconveyer member being adapted to periodically form a prolongation of anadjacent uptake, means for supplyingfuel to said retort, a hopper fordirecting fuel to said retort, and means for oscillating said conveyermembers, one of said conveyer members being located to receive all thefuel entering the retort through said hopper, contiguous conveyermembers being arranged to oscillate in opposite directions.

8. An automa-tic stoker comprising a retort provided with an imperforatebottom having spaced apart uptakes, conveyer members supportedl in aplane above said uptakes and each adapted to periodically form aprolongation of an adjacent uptake, said conveyer members being arrangedin sets, means for supplying fuel to said retort, and means foroscillating each set of conveyer members in a direction opposite to theoscillation of the members of the other set and simultaneouslytherewith, whereby said conveyer members alternately support and movethe fuel in said retort.

9. The combination with a grate, of an automatic stoker comprising aretort provided with an imperforate bottom having spaced apart uptakes,conveyer members supported in a plane above said uptakes and cooperatingwith said uptakes, one face of each conveyer being adapted toperiodically form a prolongation of an adjacent uptake, means forsupplying fuel to said retort, means for oscillating said conveyermembers, and grate bars spanning the space between said grate and saidretort, contiguous conveyer members being arranged to oscillate inopposite directions, whereby the fuel in said retort is alternatelylifted to said grate bars and moved through said retort.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

WALTER F. SMITH.

VWitnesses:

JULIUs I-I. VVYMAN, DWIGHT M. LUDINGTON.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

